Alan C.

I recently purchased a set of high flow cats for the 02 996. When I started to install them I found that the O2 sensors would not connect like the OEM cats. The sensor down stream of the header connects to the same OE location. However the sensor after the cat will now have to hook to the opposite side due to the sensor location in the pipe. The sensor bung on the driver side cat lies directly beneath the passenger side O2 sensor, the reverse for the other side. In effect the muffler side sensors will be crossed. Of course I could splice and lengthen the wires but I'd rather not modify the OE wires.

Any thoughts on this being an issue as the cross is after the cats. Still kind of strange.

Tbred911

Hi Alan,

if you go to fabspeed.com you will see they have a video featuring their high flow cats... I'm not making a pitch here for fabspeed products but their video was very educational in that they explained how the stock porsche cats have 2 cats per pipe (4 cats total) and how the bungs in the middle of the cat is actually *after* the first cat... I don't know what impact this would have if you lengthened the wires but after watching that video it seems it shouldn't have any impact at all given the 2ndary cats are kind of redundant.

Alan C.

Thanks Pete,
I know the 2 O2 sensors have to do with OBDII. The ones after the cat may not have much of an impact. I'll check Fabspeeds site.

Tbred911

... no prob...

the O2 sensors after the cat need to be hooked up.... or else you will get a CEL and eventually go into limp mode and your call will lose performance